Xref: utzoo comp.os.vms:10198 comp.periphs:1317
Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ncar!tank!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.os.vms,comp.periphs
Subject: Re: Megatape 8mm backup device
Message-ID: <14653@mimsy.UUCP>
Date: 20 Nov 88 23:14:48 GMT
References: <8811012326.AA26528@ucbvax.Berkeley.EDU> <14304@mimsy.UUCP> <14650@mimsy.UUCP>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 28

Some corrections to article <14650@mimsy.UUCP> (by me):
>The Megatape box has a 512 kB cache ....

Steve said `Oops, make that 1.2MB or 1.5MB'.  (Well, that too was not
in the manual, or I missed it, but apparently it was a recent change
that improved performance [I would guess so---why manufacturers think
less than 1 MB is a `big' cache is beyond me...].  Preliminary manuals
can be expected to need changes, I suppose.)

>You will have some trouble if you cannot prevent your TS11 driver from
>attempting to backspace by records or files, as these units cannot do
>this ....

Bill Wyatt (at Harvard's CFA) tells me that backspace by file is
possible, but to backspace over a tape mark, they will have to use the
`long' tape mark format.  I got errors back from the TC13 after each
attempt to write after a backspace, so either there is a bug in the
firmware, or they are using short marks.

>... forward skips are not much faster than plain reading ...

Bill says `more like 10x'; that is considerably better: about 15
minutes to position over a full tape.

Anyway, we still like it.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris